class_docstr: Tests for the StrongConvexMixin.
docstr: Test that fn of Mixin returns None.
  
  Args:
    fn: fn of Mixin to test
    args: arguments to fn of Mixin
docstr_tok: ["Test","that","fn","of","Mixin","returns","None",".","Args",":","fn",":","fn","of","Mixin","to","test","args",":","arguments","to","fn","of","Mixin"]
code: def test_return_none(self, fn, args):
      """Test that fn of Mixin returns None.
  
      Args:
        fn: fn of Mixin to test
        args: arguments to fn of Mixin
      """
      loss = StrongConvexMixin()
      ret = getattr(loss, fn, None)(*args)
      self.assertNone(ret)
  
imports: from contextlib import contextmanager
  from io import StringIO
  import sys
  from absl.testing import parameterized
  import tensorflow.compat.v1
  from tensorflow.compat.v1.python.framework import test_util
  from tensorflow.compat.v1.python.keras import keras_parameterized
  from tensorflow.compat.v1.python.keras.regularizers import L1L2
  from tensorflow_privacy.privacy.bolt_on.losses import StrongConvexBinaryCrossentropy
  from tensorflow_privacy.privacy.bolt_on.losses import StrongConvexHuber
  from tensorflow_privacy.privacy.bolt_on.losses import StrongConvexMixin
label_desc: Use image node_id 2 for calling the StrongConvexMixinTests obj's underlying member method code with example usage: obj.test_return_none(fn, args) without return types